1. Field of the Invention
The present invention relates to a lens periphery edge processing apparatus for grinding a periphery edge of an objective lens to a lens shape such as a lens frame shape or mold shape of eyeglasses.
2. Description of the Prior Art
In conventional lens periphery edge processing apparatus, a reference globe is put and held between a lens rotating shafts instead of an objective lens, a carriage supporting the lens rotating shafts is lowered so that the reference globe is contacted with a grindstone, the location of the carriage at this time is detected, corrected data of the inter-shaft distance between a grindstone rotating shaft and the lens rotating shafts are obtained on the basis of the detected location data, and then, the reference globe is detached and the objective lens is put and held between the lens rotating shafts, the inter-shaft distance is corrected on the basis of said corrected data, and the vertical movement of the carriage is controlled, thereby the objective lens is ground.
However, in the above-mentioned conventional lens periphery edge processing apparatus, in case where an initial set is performed whenever the objective lens is processed, the corrected data is obtained by inserting the reference globe to the lens rotating shafts, and then, the reference globe is detached, and the objective lens should be put and held between the lens rotating shafts. Accordingly, there are problems that the operation for inserting or detaching the reference globe is complicated, and considerable time is required.
The object of the present invention is to provide a lens periphery edge processing apparatus in which the operation or inserting or detaching the reference globe does not need to be inserted or detached.
According to the present invention, there is provided the lens periphery edge processing apparatus comprising lens rotating shafts for putting and holding an objective lens therebetween, a carriage rotatable around a pivot, and a grindstone rotating shaft provided with a grindstone for grinding the objective lens, wherein a reference globe having a predetermined radius is fixed to one of said rotating shafts.